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All the drivers in the Bose system are 2 ohm, and high efficiency too with light cones and pretty strong neodymium magnets.
I don't know if replacing the Bose 10-inch door woofers with other drivers will yield an improvement in sound. I just don't know. Those drivers handle a lot of the lower mids / mids, and so maybe you'd have an improvement there in clarity and definition with some other driver. I think those 10 inch drivers have a pretty low Fs though, and in a door mount- which is not really an enclosure at all- I think your lowest bass performance is going to be closely linked to Fs, and I'll bet you those 10 inch drivers have a lower Fs than any 8 inch driver you can put in there. This is just a guess, though, I don't know what the Fs (free-air resonance frequency) of the Bose drivers is.
The Earthquake Sound SWSs 8X has an Fs (they call it Fo) of 30 Hz. The Earthquake Sound SWSs have greater excursion, but also have fairly low efficiency at 86 dB - I'll bet you the Bose woofers have closer to 90 dB efficiency, maye even higher. Also since the Earthquake Sound SWSs seem to be designed to be used as under-seat dedicated subs and so I wonder how good their definition and detail will be if used up into the lower midrange the way the Bose 10-inch drivers are. I'd like to at lease see a FR graph of the Earthquake Sound SWSs.
It might be tricky to get those Earthquake Sound SWSs mounted in the G37 doors, the Earthquake Sound SWSs have a mounting depth of 2 1/16" I wonder if that's more than the Bose 10 inch pancake. The Earthquake Sound SWSs ARE 2-ohm, however, so that part is good. I wish I could hear them in a G37....
I've been looking of pictures of the door subs.... there may be room to play, even with a 10" shallow mount sub which would definitely have a low enough Fs. The other issue would be choosing a sub with the right parameters for IB but good enough response in the mid/"high" bass region for sound quality. There is definitely directionality and stuff in the ~300-600Hz range.
The efficiency is not that big of a concern for me; if I went as far as to put new subs in the doors I would amp them separately. I think NVX makes some tiny D-class amps I could mount either under the seats or in the doors. I know there are concerns about rattles with age but my car is a 2012; I can't imagine it getting much worse with a little more power and I know the last user also listened to bass heavy rap.
Originally Posted by milosz
What I've heard regarding replacing the 10-inch shallow profile Bose driver (subwoofer, so-called) in the rear shelf is that it's hard to get a driver in there... there's not much clearance between the deck and window, dropping a driver down in there is hard / impossible depending on the height of the driver. And using a low profile driver in there, I dunno, would it be worth it? Wouldn't it sound quite similar (if marginally better-) than the 10 inch low profile Bose driver in there?
For bass, I always prefer the sound of a sealed box, there's better transient performance and lower group delay down low. But that's just me, I went with what I knew would give me the sound I want.
From what I've seen, the issue with the rear parcel sub is the height in front of the mounting plate, as well as getting to the screws by the window. There are a few ways to deal with that.... 1 is to get a sub with a low mounting... height?.... which there are a few of for sure. 2 is to mount the sub under the parcel, which is tricky but would work well if done right. 3 is to mount it on the parcel but keep the screws holes away from the rear window. I've used ratchets to get screws in so I could figure something out.
I've always preferred the sound of a ported box so running IB would be close. Plus admittedly a lot of my source material is not the best quality.... 128kbps MP3s from my college days don't deserve too much effort But like the door subs I would amp these too.
I do know someone mounted a deep JL Audio 10" in the rear parcel, though they had to do some cutting... I'd be OK with that. I don't think depth is a huge concern; it's the height in front of the flange.
Originally Posted by milosz
I will get some frequency response plots of the left / right / center outputs of the Bose head unit when I break into those lines to install my MiniDSP's. I also think it would be useful to try and measure the signal going from the Bose trunk-mounted amplifier to the door-mounted mid, and also measure what the FR looks like of the signal going from the Bose amp to the door-mounted 10-inch driver. Having both the head-unit line level FR and the output FR of the amp driving the speakers will tell you if there's EQ and where it is being done. I suspect the EQ comes from the amplifier module, Bose usually pairs an amplifier with speakers. And I think the head unit is actually mfg. by Clarion, not Bose.
The Bose amplifiers have integrated circuits inside that are labelled BOSE that look to be the "class D" amplifier control chips- they drive pairs of MOSFETS mounted on smallish heat sinks with decent size series inductors, as you'd expect for output circuits of "class D" amps- and I think the BOSE chips could have EQ baked into them also, frequencies and level selectable by SMD resistors or capacitors, or which there are many inside the amps.
Great to know that the door speakers are powered by amps from the trunk! That will make install way easier. Yea I am eagerly awaiting your FR tests. If the signals coming into the Bose amps are flat and the signals to the mids are full range I will feel a lot better about replacing everything, or at least the door and rear parcel woofers. Again I'm not going for competition grade SQ, my ears are admittedly not that discerning. My main concerns are that harshness from the front stage, and the weird stuff going on with the low end volume capping.
Plus admittedly a lot of my source material is not the best quality.... 128kbps MP3s from my college days don't deserve too much effort
the best audio components you can buy won't be able to fix the sound quality of those. i wouldnt bother with anything until you upgrade your source material.
128k MP3's can be sort of OK if they were compressed with care and a good encoder, with correct choices made for the various compression parameters. I listen to SOMA FM / GROOVE SALAD sometimes at home on good equipment and it sound OK. I notice the highs can be a little "crunchy" sometimes, there's artifact, and some recordings have less spatial depth to them when they are compressed to 128K. Groove Salad has a 256k stream now, sounds better.
For the iPod I used in my G37, I transcode music from FLAC files on my home server to 320 kbps VBR MP3 using DBPOWERAMP CONVERTER with the LAME encoder, set to the highest quality settings. I use the same 320k VBR format on DVD-R's that I make for the car from time to time. I think it's pretty cool you can play MP3 (and som other formats too) from a DVD-R (Or DVD+R, whatever) as well as have an iPod in the center console, AND play tracks from a phone via bluetooth.
I've tried to figure out which bluetooth version / codec is being used by the Bose head unit, this is not the easiest thing to determine; using a bluetooth diagnostic tool on a tablet made me more confused than when I started. Of course it depends not only on what bluetooth audio capabilities the car's head unit has, but also what the PHONE has. I dunno if the car is aptX capable or not. I know it sounds pretty decent when I stream from my phone to the car, and I did a test with an audio signal generator app on the phone, and whichever version of bluetooth audio my 2013 G37 uses, all I can say is it is definitely in stereo, and sounds like 16-bit audio. All but the latest Bluetooth codecs are not all that great in terms of kb-per-sec when compared to what can be stored on a DVD-R or an iPod; even so, for background sound or spoken word like podcasts etc, the fidelity of the bluetooth in the G37 is decent. Not great but OK. Better than it might have been- somebody did at least understand that the bluetooth would be used for music and not just voice when they designed the head unit. (I've read that the latest iterations of bluetooth audio can handle 384 kb 24-bit lossless stereo... but these are pretty recent developments and the car for sure would not have such a capability)
I've noticed that some of the subtle things I can hear on my home gear are just lost amid the road noise / wind noise in the car. I'm pretty comfortable with the 320 kbps Mp3's.
I've been looking of pictures of the door subs.... there may be room to play, even with a 10" shallow mount sub which would definitely have a low enough Fs. The other issue would be choosing a sub with the right parameters for IB but good enough response in the mid/"high" bass region for sound quality. There is definitely directionality and stuff in the ~300-600Hz range.
The efficiency is not that big of a concern for me; if I went as far as to put new subs in the doors I would amp them separately. I think NVX makes some tiny D-class amps I could mount either under the seats or in the doors. I know there are concerns about rattles with age but my car is a 2012; I can't imagine it getting much worse with a little more power and I know the last user also listened to bass heavy rap.
From what I've seen, the issue with the rear parcel sub is the height in front of the mounting plate, as well as getting to the screws by the window. There are a few ways to deal with that.... 1 is to get a sub with a low mounting... height?.... which there are a few of for sure. 2 is to mount the sub under the parcel, which is tricky but would work well if done right. 3 is to mount it on the parcel but keep the screws holes away from the rear window. I've used ratchets to get screws in so I could figure something out.
I've always preferred the sound of a ported box so running IB would be close. Plus admittedly a lot of my source material is not the best quality.... 128kbps MP3s from my college days don't deserve too much effort But like the door subs I would amp these too.
I do know someone mounted a deep JL Audio 10" in the rear parcel, though they had to do some cutting... I'd be OK with that. I don't think depth is a huge concern; it's the height in front of the flange.
Great to know that the door speakers are powered by amps from the trunk! That will make install way easier. Yea I am eagerly awaiting your FR tests. If the signals coming into the Bose amps are flat and the signals to the mids are full range I will feel a lot better about replacing everything, or at least the door and rear parcel woofers. Again I'm not going for competition grade SQ, my ears are admittedly not that discerning. My main concerns are that harshness from the front stage, and the weird stuff going on with the low end volume capping.
The "volume capping" may be some kind of dynamic limiting in the Bose amps that drive the woofer(s). I have run sine tones into the system and increased the volume until either there is a lot of audible doubling or until buzzing / rattling / vibrations became quite audible, and I did not run into anything that seemed like an electronic limit to the drive level- amplifier clipping -yes. Limit of linear driver behavior - yes. Crap rattling and buzzing-yes. But nothing that seemed like the system itself capping the output level. But then, I have disconnected my rear-shelf Bose sub, so maybe it's the amplifier for this 10-inch driver that has some kind of output limiter.
Replacing the door-mounted woofers with some other drivers presents some design issues, I think. Those 10-inch drivers in the doors are used as woofers, not just as sub-woofers. Seems to me they are used up to 1,000 Hz and beyond; using that JL Audio TW3 up that high presents problems - this is a high-mass cone and is designed specifically as a sub, and JL doesn't publish the response curve. Just a guess that this driver won't do well above about 200 Hz. Might be good in the rear package shelf but in the doors I think there's not enough quality response above 200 Hz.
I don't think I'd want to use this driver above 200 Hz.
I can't find any low-profile 10-inch drivers that are not dedicated subwoofers. But there are lots of 8" and 6.5" drivers that are designed as mid-woofers, and I'm sure some of these could fit, except they wouldn't have quite the low frequency extension of the Bose 10-inch units. Lots of folks seem to replace the Bose amps and replace the front door drivers with some kind of 6.5-inch "component" system. I just can't picture this working as well as the Bose 10 inch units down below 100 Hz, although maybe they do work fine. Dunno, never heard any setup like that.
The Bose paper cone 10 inch drivers in the doors are designed to work with those 3.5" "midrange" drivers in the doors. Those 3.5" midrange drivers have no real enclosure, and so neither would any other driver you put in there. To get a 3.5" driver to work down to below about 400 Hz you really need a proper, purpose-designed enclosure. And there's no room in there for an enclosure, which would have to be a few liters in volume at least.
Someone posted here that they were going to use a Scanspeak ScanSpeak Discovery D7608/9200-10 3" Dome Midrange, it looks like it would fit. Here's it's published response curve:
scanspeak 3" midrange dome response
That doesn't look to me like it would work crossed over to a 10-inch or 8-inch low-profile sub that really doesn't work above 200 Hz. It might work OK with a 6.5" or 8" mid-woofer, with the right crossover.
Looking at other drivers like PeerlessTC9FD18-08 3-1/2" Full Range Paper Cone Woofer, or the Peerless TG9FD-10-04 3-1/2" Glass Fiber Cone Full Range which both look like they might fit (the Bose driver is 83 mm wide and 40 mm tall, so you need somehting near that size.) - The issue here is that without an enclosure, response down below 400 Hz is going to be rolling off quite fast and / or be pretty peaky. By the way, of these two Peerless drivers the one I like best is the paper cone driver, I think it would have the most neutral sound.... but might not sound significantly better than the stock Bose driver....
I have a pair of Infinity Kappa-Perfect 300 drivers that I got to test for the car. I also have a pair of Polk Audio DB351 I could remove the tweeters from.... and a pair of the Dynaudio midrange domes that are used in some Volvo models- used, from eBay, anyway I am going to test all of these drivers to see what their response looks like. I'll be posting all that in the fullness of time.
Replacing drivers however does run into the issue of balancing the sound and also max SPL. If you simply replace the 3.5" mid with some other driver, for sure it's efficiency will be lower than the Bose driver, and unless you then adjust the level of the Bose door woofer amp downward, things will not be right. And then maybe you will find you can't crank the volume up to the level you want, there just isn't enough from the 3.5" driver given whatever amp power Bose has dedicated to driving their mid/high driver now driving the less-efficient Peerless (or Infinity or ScanSpeak, or Focal, or what-have-you.) Also I do not know if Bose applies EQ to the signal that drives these 3.5 inchers, I suspect they do, so that means if you replace the driver you need to replace the amp too. More cost and complication.... of course in the name of good sound we can justify anything.....
My approach is stepwise, see what I can do first by just using the MiniDSP as EQ and see if that "fixes" the issues, and if not, then start down the road of new drivers, amplifiers, etc etc. Along the way I am going to produce as much data as I can in order to help decide what I want to do. And I'll be posting all that here.
I would leave the 3.5" and sail tweeter in place, and amp the 10" separately. The challenge I'm seeing with the 10" is finding one that will play up to 400 or so Hz, AND have the low depth to fit in the door. This one looks interesting, though there is no FR graph:
But you are right, an 8" would probably be the best compromise, and I feel like with a low Fs + the right suspension it would have decent low end extension while still being able to cover up to where the 3.5" rolls off.
The more I look into it though, I feel like your MiniDSP EQ + either a new, separately powered sub in the rear deck or an enclosure would be the simplest and highest value way to get better SQ. The prospect of replacing the whole system is pretty daunting.
I would leave the 3.5" and sail tweeter in place, and amp the 10" separately. The challenge I'm seeing with the 10" is finding one that will play up to 400 or so Hz, AND have the low depth to fit in the door. This one looks interesting, though there is no FR graph:
But you are right, an 8" would probably be the best compromise, and I feel like with a low Fs + the right suspension it would have decent low end extension while still being able to cover up to where the 3.5" rolls off.
The more I look into it though, I feel like your MiniDSP EQ + either a new, separately powered sub in the rear deck or an enclosure would be the simplest and highest value way to get better SQ. The prospect of replacing the whole system is pretty daunting.
That does look interesting. How did I miss seeing that when I was looking around at drivers? It has a pretty high Qts which usually works OK for IB type enclosures.
And not expensive, so if they don't work out, no need to get a second job to pay for them....
That does look interesting. How did I miss seeing that when I was looking around at drivers? It has a pretty high Qts which usually works OK for IB type enclosures.
And not expensive, so if they don't work out, no need to get a second job to pay for them....
Only thing that gives me pause is the Xmax.... 10"x7mm is probably not enough for meaningful IB volume.
The more and more I think about it, doing a run of the mill enclosure setup sounds pretty good, especially with the option to run a PR. I'd get the Zenclosure box with dual 10s and tell them to remove the driver separator, and then get that Dayton HF 10" + Dayton's new PR. Recommendation is for the PR to do 1.5-2x the displacement of the driver; HF Xmax is 14mm and the new PR does 24mm. Whole thing would be tuned to like ~20Hz. My only fear is the weight, and also issues with time delay. Does the MiniDSP have that capability? Looking in the manual it appears it does.
Also when you ran your tests did you do a sweep or white noise? I feel like white noise would enable finding any resonance hot spots.
The REAL fix would be to use a different, better mid and tweeter altogether. This is hard, because the space is so limited. Not many drivers will fit. And really I don't know what frequency Bose is crossing over to the midrange driver at. Finding a driver that will match the efficiency of the existing mid and so stay in balance with the door-mount 10" bass drivers will be tricky. Of course you could always pad down the 10 inch drivers but then your total system volume level might not be high enough for your tastes.
If you're willing to do away with the 10" subs in the door, you can simply buy this adapter and fit nearly any 6.5" or 6.75" in there.
To determine the crossover points, it's quite simple I think. Download a varaible tone generator on your phone and slightly raise or lower the frequency until you hear the particular speaker cut in or out. I tried doing this but it was kind of difficult to determine which specific frequencies, with multiple speakers outputting sound, as the speakers do overlap frequency ranges. I believe the sub cuts off at around 200 Hz and the mids cut in at around 100Hz, but don't quote me. The best way to do this would be to simply disconnect one of the speakers so you can tell more definitively when the other cuts in/out.
To determine the crossover points, it's quite simple I think. Download a varaible tone generator on your phone and slightly raise or lower the frequency until you hear the particular speaker cut in or out. I tried doing this but it was kind of difficult to determine which specific frequencies, with multiple speakers outputting sound, as the speakers do overlap frequency ranges. I believe the sub cuts off at around 200 Hz and the mids cut in at around 100Hz, but don't quote me. The best way to do this would be to simply disconnect one of the speakers so you can tell more definitively when the other cuts in/out.
I don't know that a 6.5" or 6.75" driver would be an improvement over a 10". Let's look at the math:
A 10 inch driver has a cone area of about 80 square inches; a 6.5 inch driver has a cone area of 33 square inches. The 6.5" driver would need nearly 2½ times the excursion of the 10 inch driver just to move the same amount of air. To offer better bass than the 10 inch driver it would need to have at least 3 times the excursion.... so I don't really see what you gain by going to a 6.5 inch driver from the Bose 10. Better resolution in the mids, maybe?
I don't know that a 6.5" or 6.75" driver would be an improvement over a 10". Let's look at the math:
A 10 inch driver has a cone area of about 80 square inches; a 6.5 inch driver has a cone area of 33 square inches. The 6.5" driver would need nearly 2½ times the excursion of the 10 inch driver just to move the same amount of air. To offer better bass than the 10 inch driver it would need to have at least 3 times the excursion.... so I don't really see what you gain by going to a 6.5 inch driver from the Bose 10. Better resolution in the mids, maybe?
Oh yeah, I'm sure that the 10" subs will outperform many smaller drivers as far as midbass (100 - 250Hz) goes. Though if you spend enough, there are definitely many which I'm sure would outperform them. I say this because like the sub you'd put in your trunk the 10's excel in the sub bass frequencies. I think I remember this from when I was doing my tone generator testing that I mentioned. So, as long as you have a sub in your trunk, which should be the first step you take before any of this, I don't think you'd miss the 10's that much, if at all.
The main point would obviously be superior mids clarity. And honestly, it would probably the easiest route. That is, just sweeping the entire Bose system and starting fresh like a previous member has mentioned. You don't need to worry about matching anything to OEM speakers. Even more so, no need to worry about matching new 2.8" mid drivers to some independent tweeters, as a component system will be paired with them. New crossovers can be used. And you don't need to worry about fitment that much.
So honestly, I'm now beginning to realize this is the best approach, as many tech advisors have mentioned to me. The downside of losing the 3-way system doesn't outweigh the difficulty of properly implementing everything that's been discussed here.
HOWEVER If you do not want to elect to go that route, here are some pretty good mids that should fit in almost perfectly. They are the near exact same size as oem. AND, they also have tweeters to match, which is hugely important when it comes to achieving awesome overall sound.
So Hotsawze are you saying to ditch the 3 way setup and do a 2 way in the doors? That would make things easier, though I wonder if ditching the sail tweeters will make interactions with the center channel wonky.
I still like the sub box + MiniDSP idea though, with the frequency response tuned to pink noise. I am just certain there are some "brightness" hot spots. That may be enough to start with.
So Hotsawze are you saying to ditch the 3 way setup and do a 2 way in the doors? That would make things easier, though I wonder if ditching the sail tweeters will make interactions with the center channel wonky.
I still like the sub box + MiniDSP idea though, with the frequency response tuned to pink noise. I am just certain there are some "brightness" hot spots. That may be enough to start with.
Well, what I'm saying is that the results you'd achieve relative to the ease of doing so would probably be best by just going with a 2-way. However, it'll be a bit more pricey because of the speakers themselves and needing a bigger amp. You'd now be losing out on the 70 watts going to each 10" woofer.
Before you worry about the mid range, you should definitely get a sub first. I have two 10's.
If you have good sub(s) in the trunk you can rely on them at least up to 100 Hz, maybe higher. A 100 Hz sound wave has a wavelength of 11.3 feet.... you're not going to have directional cues at such frequencies that tell you "coming from trunk" vs "coming from font"
So, certainly, if you're not using the Bose door 10-inch drivers for bass "impact" at all, and using your subs for that, there are many good 6.5 inch "component" auto sound drivers out there in terms of detail and clarity through their intended range. There are also lots of even better "hi fi" drivers from SEAS, Scanspeak, Morel, Dynaudio, Satori and so on. Of course this approach will require new amplifiers that don't have EQ built into them for the Bose drivers the way the stock amp has, and you'll need an electronic crossover of some kind; and you can either go with 6.5 / 7-inch to replace the 10-inch driver then put a good quality tweeter where the Bose 3.5" midrange was and forget about that little dome in the sail. That could be a great-sounding system- but don't forget you've got a Bose 3.5" driver in the dash and the stock G37 head-unit uses that "channel" to help with staging and so on, so you'r need to think about that driver, it's EQ and so on. In this "redesign" type setup, that center driver requires some careful consideration. Maybe just EQing it and using a small aftermarket amp could help it "blend" into the overall new system.
One of the issues when using "hi fi" drivers like SEAS / Scanspeak / Satori is they are designed to work best at room temperature. using them at -5° F, well, they won't work quite as designed. And I'm not sure they will enjoy sitting in a car all day in a hot Arizona parking lot baking while you are at work.... my own favorites are SEAS, Scanspeak and Satori, I have used them all in some good sounding home box speakers, though I tend to favor the new Bozhen ribbon tweeter over tweeters from any of those companies. Ribbon tweeters don't fit in car doors.... neither would the tri-amped Magneplanar 3.6's or restored Quad ESL-57's that I listen to at home.... hahaha...Though at one time there WAS an electrostatic system designed for car use.... and Martin Logan has tried to create them too
I have gotten one of the Bose 3.5 midrange drivers as mounted in the front doors of the G37 sedan, and I ran some tests on it...
Here's the driver, showing the cone, and the magnet
G37 Bose 3.5 inch midrange driver
G37 Bose 3.5 inch midrange driver magnet
Here's the test setup - the driver is mounted in a wooden baffle, open to the back; behind stands a large slab of acoustic foam to keep any sound from the back of the driver bouncing off the rear wall of the room and coming back through the driver...
You can see the little Dell Windows 10 tablet there running the measurement software, and the Lepai lp7498e amplifier used to drive the speaker for testing.
Here's a closer shot of the driver and the measurement mic; this is a close mic measurement, the intent is to measure the driver not room reflections etc.
Here's the frequency response of the driver, along with distortion curves. Black line is frequency response; blue curve is total harmonic distortion, red is 2nd harmonic, and so on. 1/8 octave smoothing used.
Pretty flat response up above 1 kHz, and response below 1 kHz isn't bad either, though response below 1 kHz becomes increasingly dependent on the "enclosure" in the door as you go down in frequency, and will not show as strong a response below 300 Hz as this close-mic measurement indicates.
Here's the waterfall plot - and here we see what I think is the culprit for the false brightness that seems to characterize this system- there are prominent ridges of stored energy from about 4 kHz to 10 kHz, with the strongest being at 6 khz.
I would say that this is actually quite a good driver- but it should not be driven above 5 kHz. This driver should have a second order low-pass filter in series with it, centered at 5 kHz.
Here's the impedance plot - note this graph has no magnitude units on the Y axis, the impedance indicated there is relative only. The equipment I used to get this plot isn't calibrated in terms of magnitude.
Making manual measurements, measurements that ARE calibrated in terms of impedance magnitude, I find the impedance peaks at 39 ohms at 211 Hz, this must be the free-air resonance of this driver. The nominal impedance of this driver is 4 ohms. THIS IS NOT A 2 OHM DRIVER as stated elsewhere. This is a 4 ohm driver.
And finally, I measured 95 dB SPL at 1 kHz at 1 meter with 1 watt of drive, so this a fairly efficient driver, but not insanely so.
05-20-2017, 09:26 AM
But like the door subs I would amp these too.
